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Electrothermal Acceleration
Electrothermal Acceleration was a weapon propellant technology used by The Royal Allegiance during the Swarm War. History Usage The technique was used in virtually all larger calibre projectile weapons. It meant that otherwise relatively standard cannons could be substantially increased in lethality. They had greater muzzle velocities, which aided in range and accuracy, as well as penetration characteristics. The effect of this was greatest in oversized calibre weapons, such as the massive 900mm M119 Heavy Naval Cannon, substantial in large calibres such as the L82 and L120 Cannons, and smallest in small arms and infantry weapons. Some infantry weapons made use of the principle, but they largely remained with the less energy intensive and simpler chemical propellants, or ignored Electrothermal acceleration and instead went for energy demanding but massively more powerful Particle Cannons. Cannons were the most widespread weapons to use electrothermal propellant, mainly warship, turret and tank mounted guns. A notable small arm that used the electrothermal acceleration method was the M8 Submachine Gun, quite possibly the most successful of its type. Design The Electrothermal Acceleration system used a plasma discharge rather than a chemical reaction to force the shell down the barrel. A high current, high voltage energy source was used along with a large Capacitor bank. Both were attached in series to the electrode system in the cannon's barrel. The capacitor was loaded with as high a voltage as possible. However, a militarily useful energy was achieved with as little as several kilojoules. The capacitor was then discharged. The gas in the gap between the electrodes would ionise, turning the non-flammable propellant into superheated conductive plasma. At this point, associated volumetric expansion would propel the projectile from the barrel at very high velocity. In spatial combat, there was no gas and no atmosphere to ionise to propel the round. Therefore warship-based cannons had injectors that filled the chamber with gas, usually a chemically inert noble gas with high ionisation energy, which then allowed the weapon to fire. The disadvantage of this was that larger amounts of energy were needed to ionise the gas, however warships could easily meet this requirement. The advantages of this method of propellant were clear. It increased the round's velocity by up to 480% over conventional techniques, aiding in accuracy and penetration characteristics. It used electricity as energy source, eliminating the need for explosive and vulnerable propellants. The power of the round could also be determined, unlike traditional methods. The more energy was supplied the faster the gases expanded, and the faster the projectile was accelerated. This made it possible to select any velocity desired and also allowed the projectile to reach speeds at which it would outrun the burn rate of a conventional propellant. The largest conventional cannon using this system was the M119 Heavy Naval Cannon. It had a muzzle velocity of 34,272 kph, allowing it far greater range, penetration and accuracy over older, more traditional cannons. Electrothermal Accleration cannons also benefited from substantialy decreased muzzle flash, and did not suffer the same heat problems that plagued railguns of similar muzzle velocities.